diff options
| -rw-r--r-- | include/linux/user_events.h | 53 | ||||
| -rw-r--r-- | include/uapi/linux/user_events.h | 15 | ||||
| -rw-r--r-- | kernel/trace/Kconfig | 5 | ||||
| -rw-r--r-- | kernel/trace/trace_events_user.c | 586 |
4 files changed, 517 insertions, 142 deletions
diff --git a/include/linux/user_events.h b/include/linux/user_events.h index 3d747c45d2fa..0120b3dd5b03 100644 --- a/include/linux/user_events.h +++ b/include/linux/user_events.h @@ -9,13 +9,63 @@ #ifndef _LINUX_USER_EVENTS_H #define _LINUX_USER_EVENTS_H +#include <linux/list.h> +#include <linux/refcount.h> +#include <linux/mm_types.h> +#include <linux/workqueue.h> #include <uapi/linux/user_events.h> #ifdef CONFIG_USER_EVENTS struct user_event_mm { + struct list_head link; + struct list_head enablers; + struct mm_struct *mm; + struct user_event_mm *next; + refcount_t refcnt; + refcount_t tasks; + struct rcu_work put_rwork; }; -#endif +extern void user_event_mm_dup(struct task_struct *t, + struct user_event_mm *old_mm); + +extern void user_event_mm_remove(struct task_struct *t); + +static inline void user_events_fork(struct task_struct *t, + unsigned long clone_flags) +{ + struct user_event_mm *old_mm; + + if (!t || !current->user_event_mm) + return; + + old_mm = current->user_event_mm; + + if (clone_flags & CLONE_VM) { + t->user_event_mm = old_mm; + refcount_inc(&old_mm->tasks); + return; + } + + user_event_mm_dup(t, old_mm); +} + +static inline void user_events_execve(struct task_struct *t) +{ + if (!t || !t->user_event_mm) + return; + + user_event_mm_remove(t); +} + +static inline void user_events_exit(struct task_struct *t) +{ + if (!t || !t->user_event_mm) + return; + + user_event_mm_remove(t); +} +#else static inline void user_events_fork(struct task_struct *t, unsigned long clone_flags) { @@ -28,5 +78,6 @@ static inline void user_events_execve(struct task_struct *t) static inline void user_events_exit(struct task_struct *t) { } +#endif /* CONFIG_USER_EVENTS */ #endif /* _LINUX_USER_EVENTS_H */ diff --git a/include/uapi/linux/user_events.h b/include/uapi/linux/user_events.h index 03f92366068d..22521bc622db 100644 --- a/include/uapi/linux/user_events.h +++ b/include/uapi/linux/user_events.h @@ -27,12 +27,21 @@ struct user_reg { /* Input: Size of the user_reg structure being used */ __u32 size; + /* Input: Bit in enable address to use */ + __u8 enable_bit; + + /* Input: Enable size in bytes at address */ + __u8 enable_size; + + /* Input: Flags for future use, set to 0 */ + __u16 flags; + + /* Input: Address to update when enabled */ + __u64 enable_addr; + /* Input: Pointer to string with event name, description and flags */ __u64 name_args; - /* Output: Bitwise index of the event within the status page */ - __u32 status_bit; - /* Output: Index of the event to use when writing data */ __u32 write_index; } __attribute__((__packed__)); diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 5b1e7fa41ca8..c7020e071bf9 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -798,9 +798,10 @@ config USER_EVENTS can be used like an existing kernel trace event. User trace events are generated by writing to a tracefs file. User processes can determine if their tracing events should be - generated by memory mapping a tracefs file and checking for - an associated byte being non-zero. + generated by registering a value and bit with the kernel + that reflects when it is enabled or not. + See Documentation/trace/user_events.rst. If in doubt, say N. config HIST_TRIGGERS diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c index 070551480747..553a82ee7aeb 100644 --- a/kernel/trace/trace_events_user.c +++ b/kernel/trace/trace_events_user.c @@ -19,6 +19,7 @@ #include <linux/tracefs.h> #include <linux/types.h> #include <linux/uaccess.h> +#include <linux/highmem.h> #include <linux/user_events.h> #include "trace.h" #include "trace_dynevent.h" @@ -29,35 +30,12 @@ #define FIELD_DEPTH_NAME 1 #define FIELD_DEPTH_SIZE 2 -/* - * Limits how many trace_event calls user processes can create: - * Must be a power of two of PAGE_SIZE. - */ -#define MAX_PAGE_ORDER 0 -#define MAX_PAGES (1 << MAX_PAGE_ORDER) -#define MAX_BYTES (MAX_PAGES * PAGE_SIZE) -#define MAX_EVENTS (MAX_BYTES * 8) - /* Limit how long of an event name plus args within the subsystem. */ #define MAX_EVENT_DESC 512 #define EVENT_NAME(user_event) ((user_event)->tracepoint.name) #define MAX_FIELD_ARRAY_SIZE 1024 /* - * The MAP_STATUS_* macros are used for taking a index and determining the - * appropriate byte and the bit in the byte to set/reset for an event. - * - * The lower 3 bits of the index decide which bit to set. - * The remaining upper bits of the index decide which byte to use for the bit. - * - * This is used when an event has a probe attached/removed to reflect live - * status of the event wanting tracing or not to user-programs via shared - * memory maps. - */ -#define MAP_STATUS_BYTE(index) ((index) >> 3) -#define MAP_STATUS_MASK(index) BIT((index) & 7) - -/* * Internal bits (kernel side only) to keep track of connected probes: * These are used when status is requested in text form about an event. These * bits are compared against an internal byte on the event to determine which @@ -70,20 +48,14 @@ #define EVENT_STATUS_OTHER BIT(7) /* - * Stores the pages, tables, and locks for a group of events. - * Each logical grouping of events has its own group, with a - * matching page for status checks within user programs. This - * allows for isolation of events to user programs by various - * means. + * Stores the system name, tables, and locks for a group of events. This + * allows isolation for events by various means. */ struct user_event_group { - struct page *pages; - char *register_page_data; char *system_name; struct hlist_node node; struct mutex reg_mutex; DECLARE_HASHTABLE(register_table, 8); - DECLARE_BITMAP(page_bitmap, MAX_EVENTS); }; /* Group for init_user_ns mapping, top-most group */ @@ -106,13 +78,35 @@ struct user_event { struct list_head fields; struct list_head validators; refcount_t refcnt; - int index; - int flags; int min_size; char status; }; /* + * Stores per-mm/event properties that enable an address to be + * updated properly for each task. As tasks are forked, we use + * these to track enablement sites that are tied to an event. + */ +struct user_event_enabler { + struct list_head link; + struct user_event *event; + unsigned long addr; + + /* Track enable bit, flags, etc. Aligned for bitops. */ + unsigned int values; +}; + +/* Bits 0-5 are for the bit to update upon enable/disable (0-63 allowed) */ +#define ENABLE_VAL_BIT_MASK 0x3F + +/* Only duplicate the bit value */ +#define ENABLE_VAL_DUP_MASK ENABLE_VAL_BIT_MASK + +/* Global list of memory descriptors using user_events */ +static LIST_HEAD(user_event_mms); +static DEFINE_SPINLOCK(user_event_mms_lock); + +/* * Stores per-file events references, as users register events * within a file this structure is modified and freed via RCU. * The lifetime of this struct is tied to the lifetime of the file. @@ -145,33 +139,17 @@ static int user_event_parse(struct user_event_group *group, char *name, char *args, char *flags, struct user_event **newuser); +static struct user_event_mm *user_event_mm_get(struct user_event_mm *mm); +static struct user_event_mm *user_event_mm_get_all(struct user_event *user); +static void user_event_mm_put(struct user_event_mm *mm); + static u32 user_event_key(char *name) { return jhash(name, strlen(name), 0); } -static void set_page_reservations(char *pages, bool set) -{ - int page; - - for (page = 0; page < MAX_PAGES; ++page) { - void *addr = pages + (PAGE_SIZE * page); - - if (set) - SetPageReserved(virt_to_page(addr)); - else - ClearPageReserved(virt_to_page(addr)); - } -} - static void user_event_group_destroy(struct user_event_group *group) { - if (group->register_page_data) - set_page_reservations(group->register_page_data, false); - - if (group->pages) - __free_pages(group->pages, MAX_PAGE_ORDER); - kfree(group->system_name); kfree(group); } @@ -242,19 +220,6 @@ static struct user_event_group if (!group->system_name) goto error; - group->pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, MAX_PAGE_ORDER); - - if (!group->pages) - goto error; - - group->register_page_data = page_address(group->pages); - - set_page_reservations(group->register_page_data, true); - - /* Zero all bits beside 0 (which is reserved for failures) */ - bitmap_zero(group->page_bitmap, MAX_EVENTS); - set_bit(0, group->page_bitmap); - mutex_init(&group->reg_mutex); hash_init(group->register_table); @@ -266,20 +231,367 @@ error: return NULL; }; -static __always_inline -void user_event_register_set(struct user_event *user) +static void user_event_enabler_destroy(struct user_event_enabler *enabler) +{ + list_del_rcu(&enabler->link); + + /* No longer tracking the event via the enabler */ + refcount_dec(&enabler->event->refcnt); + + kfree(enabler); +} + +static int user_event_mm_fault_in(struct user_event_mm *mm, unsigned long uaddr) +{ + bool unlocked; + int ret; + + mmap_read_lock(mm->mm); + + /* Ensure MM has tasks, cannot use after exit_mm() */ + if (refcount_read(&mm->tasks) == 0) { + ret = -ENOENT; + goto out; + } + + ret = fixup_user_fault(mm->mm, uaddr, FAULT_FLAG_WRITE | FAULT_FLAG_REMOTE, + &unlocked); +out: + mmap_read_unlock(mm->mm); + + return ret; +} + +static int user_event_enabler_write(struct user_event_mm *mm, + struct user_event_enabler *enabler) +{ + unsigned long uaddr = enabler->addr; + unsigned long *ptr; + struct page *page; + void *kaddr; + int ret; + + lockdep_assert_held(&event_mutex); + mmap_assert_locked(mm->mm); + + /* Ensure MM has tasks, cannot use after exit_mm() */ + if (refcount_read(&mm->tasks) == 0) + return -ENOENT; + + ret = pin_user_pages_remote(mm->mm, uaddr, 1, FOLL_WRITE | FOLL_NOFAULT, + &page, NULL, NULL); + + if (ret <= 0) { + pr_warn("user_events: Enable write failed\n"); + return -EFAULT; + } + + kaddr = kmap_local_page(page); + ptr = kaddr + (uaddr & ~PAGE_MASK); + + /* Update bit atomically, user tracers must be atomic as well */ + if (enabler->event && enabler->event->status) + set_bit(enabler->values & ENABLE_VAL_BIT_MASK, ptr); + else + clear_bit(enabler->values & ENABLE_VAL_BIT_MASK, ptr); + + kunmap_local(kaddr); + unpin_user_pages_dirty_lock(&page, 1, true); + + return 0; +} + +static void user_event_enabler_update(struct user_event *user) +{ + struct user_event_enabler *enabler; + struct user_event_mm *mm = user_event_mm_get_all(user); + struct user_event_mm *next; + + while (mm) { + next = mm->next; + mmap_read_lock(mm->mm); + rcu_read_lock(); + + list_for_each_entry_rcu(enabler, &mm->enablers, link) + if (enabler->event == user) + user_event_enabler_write(mm, enabler); + + rcu_read_unlock(); + mmap_read_unlock(mm->mm); + user_event_mm_put(mm); + mm = next; + } +} + +static bool user_event_enabler_dup(struct user_event_enabler *orig, + struct user_event_mm *mm) +{ + struct user_event_enabler *enabler; + + enabler = kzalloc(sizeof(*enabler), GFP_NOWAIT); + + if (!enabler) + return false; + + enabler->event = orig->event; + enabler->addr = orig->addr; + + /* Only dup part of value (ignore future flags, etc) */ + enabler->values = orig->values & ENABLE_VAL_DUP_MASK; + + refcount_inc(&enabler->event->refcnt); + list_add_rcu(&enabler->link, &mm->enablers); + + return true; +} + +static struct user_event_mm *user_event_mm_get(struct user_event_mm *mm) +{ + refcount_inc(&mm->refcnt); + + return mm; +} + +static struct user_event_mm *user_event_mm_get_all(struct user_event *user) +{ + struct user_event_mm *found = NULL; + struct user_event_enabler *enabler; + struct user_event_mm *mm; + + /* + * We do not want to block fork/exec while enablements are being + * updated, so we use RCU to walk the current tasks that have used + * user_events ABI for 1 or more events. Each enabler found in each + * task that matches the event being updated has a write to reflect + * the kernel state back into the process. Waits/faults must not occur + * during this. So we scan the list under RCU for all the mm that have + * the event within it. This is needed because mm_read_lock() can wait. + * Each user mm returned has a ref inc to handle remove RCU races. + */ + rcu_read_lock(); + + list_for_each_entry_rcu(mm, &user_event_mms, link) + list_for_each_entry_rcu(enabler, &mm->enablers, link) + if (enabler->event == user) { + mm->next = found; + found = user_event_mm_get(mm); + break; + } + + rcu_read_unlock(); + + return found; +} + +static struct user_event_mm *user_event_mm_create(struct task_struct *t) +{ + struct user_event_mm *user_mm; + unsigned long flags; + + user_mm = kzalloc(sizeof(*user_mm), GFP_KERNEL); + + if (!user_mm) + return NULL; + + user_mm->mm = t->mm; + INIT_LIST_HEAD(&user_mm->enablers); + refcount_set(&user_mm->refcnt, 1); + refcount_set(&user_mm->tasks, 1); + + spin_lock_irqsave(&user_event_mms_lock, flags); + list_add_rcu(&user_mm->link, &user_event_mms); + spin_unlock_irqrestore(&user_event_mms_lock, flags); + + t->user_event_mm = user_mm; + + /* + * The lifetime of the memory descriptor can slightly outlast + * the task lifetime if a ref to the user_event_mm is taken + * between list_del_rcu() and call_rcu(). Therefore we need + * to take a reference to it to ensure it can live this long + * under this corner case. This can also occur in clones that + * outlast the parent. + */ + mmgrab(user_mm->mm); + + return user_mm; +} + +static struct user_event_mm *current_user_event_mm(void) +{ + struct user_event_mm *user_mm = current->user_event_mm; + + if (user_mm) + goto inc; + + user_mm = user_event_mm_create(current); + + if (!user_mm) + goto error; +inc: + refcount_inc(&user_mm->refcnt); +error: + return user_mm; +} + +static void user_event_mm_destroy(struct user_event_mm *mm) +{ + struct user_event_enabler *enabler, *next; + + list_for_each_entry_safe(enabler, next, &mm->enablers, link) + user_event_enabler_destroy(enabler); + + mmdrop(mm->mm); + kfree(mm); +} + +static void user_event_mm_put(struct user_event_mm *mm) +{ + if (mm && refcount_dec_and_test(&mm->refcnt)) + user_event_mm_destroy(mm); +} + +static void delayed_user_event_mm_put(struct work_struct *work) +{ + struct user_event_mm *mm; + + mm = container_of(to_rcu_work(work), struct user_event_mm, put_rwork); + user_event_mm_put(mm); +} + +void user_event_mm_remove(struct task_struct *t) { - int i = user->index; + struct user_event_mm *mm; + unsigned long flags; + + might_sleep(); + + mm = t->user_event_mm; + t->user_event_mm = NULL; + + /* Clone will increment the tasks, only remove if last clone */ + if (!refcount_dec_and_test(&mm->tasks)) + return; + + /* Remove the mm from the list, so it can no longer be enabled */ + spin_lock_irqsave(&user_event_mms_lock, flags); + list_del_rcu(&mm->link); + spin_unlock_irqrestore(&user_event_mms_lock, flags); + + /* + * We need to wait for currently occurring writes to stop within + * the mm. This is required since exit_mm() snaps the current rss + * stats and clears them. On the final mmdrop(), check_mm() will + * report a bug if these increment. + * + * All writes/pins are done under mmap_read lock, take the write + * lock to ensure in-progress faults have completed. Faults that + * are pending but yet to run will check the task count and skip + * the fault since the mm is going away. + */ + mmap_write_lock(mm->mm); + mmap_write_unlock(mm->mm); - user->group->register_page_data[MAP_STATUS_BYTE(i)] |= MAP_STATUS_MASK(i); + /* + * Put for mm must be done after RCU delay to handle new refs in + * between the list_del_rcu() and now. This ensures any get refs + * during rcu_read_lock() are accounted for during list removal. + * + * CPU A | CPU B + * --------------------------------------------------------------- + * user_event_mm_remove() | rcu_read_lock(); + * list_del_rcu() | list_for_each_entry_rcu(); + * call_rcu() | refcount_inc(); + * . | rcu_read_unlock(); + * schedule_work() | . + * user_event_mm_put() | . + * + * mmdrop() cannot be called in the softirq context of call_rcu() + * so we use a work queue after call_rcu() to run within. + */ + INIT_RCU_WORK(&mm->put_rwork, delayed_user_event_mm_put); + queue_rcu_work(system_wq, &mm->put_rwork); } -static __always_inline -void user_event_register_clear(struct user_event *user) +void user_event_mm_dup(struct task_struct *t, struct user_event_mm *old_mm) { - int i = user->index; + struct user_event_mm *mm = user_event_mm_create(t); + struct user_event_enabler *enabler; - user->group->register_page_data[MAP_STATUS_BYTE(i)] &= ~MAP_STATUS_MASK(i); + if (!mm) + return; + + rcu_read_lock(); + + list_for_each_entry_rcu(enabler, &old_mm->enablers, link) + if (!user_event_enabler_dup(enabler, mm)) + goto error; + + rcu_read_unlock(); + + return; +error: + rcu_read_unlock(); + user_event_mm_remove(t); +} + +static struct user_event_enabler +*user_event_enabler_create(struct user_reg *reg, struct user_event *user, + int *write_result) +{ + struct user_event_enabler *enabler; + struct user_event_mm *user_mm; + unsigned long uaddr = (unsigned long)reg->enable_addr; + + user_mm = current_user_event_mm(); + + if (!user_mm) + return NULL; + + enabler = kzalloc(sizeof(*enabler), GFP_KERNEL); + + if (!enabler) + goto out; + + enabler->event = user; + enabler->addr = uaddr; + enabler->values = reg->enable_bit; +retry: + /* Prevents state changes from racing with new enablers */ + mutex_lock(&event_mutex); + + /* Attempt to reflect the current state within the process */ + mmap_read_lock(user_mm->mm); + *write_result = user_event_enabler_write(user_mm, enabler); + mmap_read_unlock(user_mm->mm); + + /* + * If the write works, then we will track the enabler. A ref to the + * underlying user_event is held by the enabler to prevent it going + * away while the enabler is still in use by a process. The ref is + * removed when the enabler is destroyed. This means a event cannot + * be forcefully deleted from the system until all tasks using it + * exit or run exec(), which includes forks and clones. + */ + if (!*write_result) { + refcount_inc(&enabler->event->refcnt); + list_add_rcu(&enabler->link, &user_mm->enablers); + } + + mutex_unlock(&event_mutex); + + if (*write_result) { + /* Attempt to fault-in and retry if it worked */ + if (!user_event_mm_fault_in(user_mm, uaddr)) + goto retry; + + kfree(enabler); + enabler = NULL; + } +out: + user_event_mm_put(user_mm); + + return enabler; } static __always_inline __must_check @@ -824,9 +1136,6 @@ static int destroy_user_event(struct user_event *user) return ret; dyn_event_remove(&user->devent); - - user_event_register_clear(user); - clear_bit(user->index, user->group->page_bitmap); hash_del(&user->node); user_event_destroy_validators(user); @@ -972,9 +1281,9 @@ discard: #endif /* - * Update the register page that is shared between user processes. + * Update the enabled bit among all user processes. */ -static void update_reg_page_for(struct user_event *user) +static void update_enable_bit_for(struct user_event *user) { struct tracepoint *tp = &user->tracepoint; char status = 0; @@ -1005,12 +1314,9 @@ static void update_reg_page_for(struct user_event *user) rcu_read_unlock_sched(); } - if (status) - user_event_register_set(user); - else - user_event_register_clear(user); - user->status = status; + + user_event_enabler_update(user); } /* @@ -1067,10 +1373,10 @@ static int user_event_reg(struct trace_event_call *call, return ret; inc: refcount_inc(&user->refcnt); - update_reg_page_for(user); + update_enable_bit_for(user); return 0; dec: - update_reg_page_for(user); + update_enable_bit_for(user); refcount_dec(&user->refcnt); return 0; } @@ -1266,7 +1572,6 @@ static int user_event_parse(struct user_event_group *group, char *name, struct user_event **newuser) { int ret; - int index; u32 key; struct user_event *user; @@ -1285,11 +1590,6 @@ static int user_event_parse(struct user_event_group *group, char *name, return 0; } - index = find_first_zero_bit(group->page_bitmap, MAX_EVENTS); - - if (index == MAX_EVENTS) - return -EMFILE; - user = kzalloc(sizeof(*user), GFP_KERNEL); if (!user) @@ -1335,14 +1635,11 @@ static int user_event_parse(struct user_event_group *group, char *name, if (ret) goto put_user_lock; - user->index = index; - /* Ensure we track self ref and caller ref (2) */ refcount_set(&user->refcnt, 2); dyn_event_init(&user->devent, &user_event_dops); dyn_event_add(&user->devent, &user->call); - set_bit(user->index, group->page_bitmap); hash_add(group->register_table, &user->node, key); mutex_unlock(&event_mutex); @@ -1559,6 +1856,37 @@ static long user_reg_get(struct user_reg __user *ureg, struct user_reg *kreg) if (ret) return ret; + /* Ensure no flags, since we don't support any yet */ + if (kreg->flags != 0) + return -EINVAL; + + /* Ensure supported size */ + switch (kreg->enable_size) { + case 4: + /* 32-bit */ + break; +#if BITS_PER_LONG >= 64 + case 8: + /* 64-bit */ + break; +#endif + default: + return -EINVAL; + } + + /* Ensure natural alignment */ + if (kreg->enable_addr % kreg->enable_size) + return -EINVAL; + + /* Ensure bit range for size */ + if (kreg->enable_bit > (kreg->enable_size * BITS_PER_BYTE) - 1) + return -EINVAL; + + /* Ensure accessible */ + if (!access_ok((const void __user *)(uintptr_t)kreg->enable_addr, + kreg->enable_size)) + return -EFAULT; + kreg->size = size; return 0; @@ -1573,8 +1901,10 @@ static long user_events_ioctl_reg(struct user_event_file_info *info, struct user_reg __user *ureg = (struct user_reg __user *)uarg; struct user_reg reg; struct user_event *user; + struct user_event_enabler *enabler; char *name; long ret; + int write_result; ret = user_reg_get(ureg, ®); @@ -1605,8 +1935,28 @@ static long user_events_ioctl_reg(struct user_event_file_info *info, if (ret < 0) return ret; + /* + * user_events_ref_add succeeded: + * At this point we have a user_event, it's lifetime is bound by the + * reference count, not this file. If anything fails, the user_event + * still has a reference until the file is released. During release + * any remaining references (from user_events_ref_add) are decremented. + * + * Attempt to create an enabler, which too has a lifetime tied in the + * same way for the event. Once the task that caused the enabler to be + * created exits or issues exec() then the enablers it has created + * will be destroyed and the ref to the event will be decremented. + */ + enabler = user_event_enabler_create(®, user, &write_result); + + if (!enabler) + return -ENOMEM; + + /* Write failed/faulted, give error back to caller */ + if (write_result) + return write_result; + put_user((u32)ret, &ureg->write_index); - put_user(user->index, &ureg->status_bit); return 0; } @@ -1720,38 +2070,6 @@ static const struct file_operations user_data_fops = { .release = user_events_release, }; -static struct user_event_group *user_status_group(struct file *file) -{ - struct seq_file *m = file->private_data; - - if (!m) - return NULL; - - return m->private; -} - -/* - * Maps the shared page into the user process for checking if event is enabled. - */ -static int user_status_mmap(struct file *file, struct vm_area_struct *vma) -{ - char *pages; - struct user_event_group *group = user_status_group(file); - unsigned long size = vma->vm_end - vma->vm_start; - - if (size != MAX_BYTES) - return -EINVAL; - - if (!group) - return -EINVAL; - - pages = group->register_page_data; - - return remap_pfn_range(vma, vma->vm_start, - virt_to_phys(pages) >> PAGE_SHIFT, - size, vm_get_page_prot(VM_READ)); -} - static void *user_seq_start(struct seq_file *m, loff_t *pos) { if (*pos) @@ -1775,7 +2093,7 @@ static int user_seq_show(struct seq_file *m, void *p) struct user_event_group *group = m->private; struct user_event *user; char status; - int i, active = 0, busy = 0, flags; + int i, active = 0, busy = 0; if (!group) return -EINVAL; @@ -1784,11 +2102,10 @@ static int user_seq_show(struct seq_file *m, void *p) hash_for_each(group->register_table, i, user, node) { status = user->status; - flags = user->flags; - seq_printf(m, "%d:%s", user->index, EVENT_NAME(user)); + seq_printf(m, "%s", EVENT_NAME(user)); - if (flags != 0 || status != 0) + if (status != 0) seq_puts(m, " #"); if (status != 0) { @@ -1811,7 +2128,6 @@ static int user_seq_show(struct seq_file *m, void *p) seq_puts(m, "\n"); seq_printf(m, "Active: %d\n", active); seq_printf(m, "Busy: %d\n", busy); - seq_printf(m, "Max: %ld\n", MAX_EVENTS); return 0; } @@ -1847,7 +2163,6 @@ static int user_status_open(struct inode *node, struct file *file) static const struct file_operations user_status_fops = { .open = user_status_open, - .mmap = user_status_mmap, .read = seq_read, .llseek = seq_lseek, .release = seq_release, @@ -1868,8 +2183,7 @@ static int create_user_tracefs(void) goto err; } - /* mmap with MAP_SHARED requires writable fd */ - emmap = tracefs_create_file("user_events_status", TRACE_MODE_WRITE, + emmap = tracefs_create_file("user_events_status", TRACE_MODE_READ, NULL, NULL, &user_status_fops); if (!emmap) { |